Tensioning mechanism for winding machines



Jam 1957 J. E. BANCROFT 2,777,643

TENSIONING MECHANISM FOR WINDING MACHINES Filed Dec. 24, 1952 3 Sheets-Sheet l INVENTOR. James E. Bancrof/ BY Mid, v62"/ 4 f/omeys TENSIONING MECHANISM FOR WINDING MACHINES Filed Dec. 24, 1952 1957 J. E. BANCROFT 3 Sheets-Sheet 2 FIIIIIH MNHWU l I I I I I l I I I l l l r IIIII I I I II IIIII mm mh I I I Iu M I I IN wmm NI u I u I 1 I A In I T WW IMH u llllllllllllllllllll J J l l|.|||.

INVETOR. Jamel? E. Bancrof/ CW, l wui, M' i Af/orheys.

Jan. 15, 1957 2,777,643

TENSIONING MECHANISM FOR WINDING MACHINES Filed Dec. 24, 1952 J. E. BANCROFT 3 Sheets-Sheet 5 INVENTOR James E Bane/0f) Af/omeys /Ml v 514 4 United States Patent IENSIONING-IVIECHANISIVI,FORWVINDIIIG 1 'MACHINES a JamesE. Bancroft, Jamaica, N. Y,, assignor to Allied Control 'C0mpany,-.Inc.,,New :York, N. Y., .a corporationpiNew York =Application-iDecembei- 24,:19S2,-Seria1-'No. 327,717

7'Claims. c1.242-'45 This invention relatesto .tensioning mechanism for use .in-winding; and reeling, machines.

:ln my'co-pendingapplication Ser. No. 162,491, filed =May 17, 19.50, now PatentNo. 2,672,298,.1 disclosea coil :w'mding machine for winding magnet coils such-as are .usedin relays-and the like. -Such machines winda--plu rality of coils simultaneously, magnet wire being-drawn -frorn;supply spools equal in'num'berto the numberof -,coils-being wound. The tension on all wires shouldbe :equal for uniformity of product and the tensioning mechzanisnrof the presentinvention is especiallyadapted for ruse-insuch machines but, as will be obvious, its use, is not limited thereto. a a

The principal object of the invention is toprovide improvedwtensioning means giving winding machines increased versatility.

.Another object is to provide tensioningmechanism adaptableforuse in the winding or-spooling-of wi-repr other filamentary materials, ribbons, and the like, capable of a widerange of: tension adjustments.

,A further object is to provide tensioning meansior ;.use with ,a-plurality of supply spools wherein the tension of the wire orother material from all spools maybe simultaneously adjusted by a single operation.

Another object is to provide improved brakingn echa- .nismfor use in tensioning means having .a -wear. compen- -;.s ation;adjustment which is independent of the tension adjustments. 7

Other, objects and advantages of the inventionwi'll in :part. appear and in part will be obvious from the following description ofvthevpresent embodiment of the invention, .taken in conjunction with the drawingsin which:

Fig. l'is a side elevation of a single tensioning unit shown in its relation to the supply spool and ,coilwinding mechanism mounted on a supportingiframe, and. attached to tension adjusting mechanism, taken on the line '11 of'Fig.3;

Fig.2 is an enlarged elevation, partly in cross-section, of the dual tensioning spring and associated parts;

Fig. 3 is a partial rear elevation showing themeans for simultaneously adjusting a plurality of tension springs;

Fig. 4 is a front elevation of the braking unit ands'pool holder;

,'Fig.'5-'isa side elevation thereof;

-'Fig.-"6 is a detail planjtaken on the line6-6. of Fig. '4; and

Pig. 7 is a fragmentary detail of one end of thetension adjustingbar showing the means for holding'the nuts in the adjusting bar','taken on the line 7'-7-of'Fig."3.

'R'eferringto Fig. l, the tensioning devices-may be-s'upported on a piperack having vertical pipeslfl, supported i-n-p'roper relation to the winding machine, to -which a're attached by clamps 11, the horizontal pipes 12 and 13. Only'one pipe 13 is shown but it Willbe'un'derstood-that several maybe-used, supporting spools at difierent levels.

lhe tensioning mechanism comprises an upper or lever -arm=prtion generally indicated at 14-secured to--pipe lzranda lower-er bralding-portion ge'nerally indicated .at-Y15 secured-to pipe 13, connected by pull 16. The

upper portionf-llis supported from a clamp 18.having :a downwardly extending yoke 19 whiehpivotally ,supports .a split block 20 in whichjs clamped a tensioning armil ble. Pull rod 1 6 is pivotallyuattached to block .20 at a point ZS-closelybehi-nd the pivotahpointlofor block 20. Arm 21extends to the rearof the supportingpipe -frame 10 andcarriesiat its rearend @a connecting block; 28 =10 which is attached the upper end of :the dual :tension spring unit, hereinafter described; which pulls downwardly on the rear endof the arm 21 thus urging theifronte nd of-the arm and ,the pulleys carried thereby upwardl y against the pull exertedthereon by the wire 30.

Thecoil or the like being-wound is; shown at 31, the .wire extending therefrom upwardly around a-roller 32,

-over.the pul leys.24 and 22, and thence downwardly to the supply spool 34. The portion of arm 21 between the .pulleys is shown as foreshortened but'in actual practice the length ofthisarm for-Wardlyof pivot 26wfll be about three timesas-long as the rear-portion-behind that pivot.

Theparts as shown in-the vdrawing are in the position operate about awrnedian position which may, for example, be horizontal.

Spool 3.4 isheld on a spindle 36 between a coil spring 38. and a slide catch -39, rotation of .the spoolrelativeto the spindle being prevented by a finger .40 which is-inserted in a hole in thegend of the spool. Spindle 36has .a splined portion 41 (Fig. 5) which has a press fit inv a cylindrical brake drum 42. The spindle is mounted in ball bearings 44, 45 in the hub 46 of a supporting clamp 48 by which it is fixed to a pipe 13. Fixed in a boss .49, also forming part of the clamp, is a forwardly extending bearing-pin 50 on which are rotatably mounted. a brake beam 51 and a yoke-shaped brake shoe supportingarm 52.

Referring to Figs. 4 and 6, a compression springs! is interposed between the cup-shaped ends of said beam and said arm as shown-at the left in the drawing, andthe beam 5-1 carries a wear-compensation adjusting'screw 55 which bears against the opposite end 56 of the arm 52 compressed to urgethe brake shoe against the brake drum. Screw 66 is threaded through a side extension 68 of clamp 48. Pull rod 16 extends through the end-of rake beam 51 and on the under side thereof is provided with a spring nut 69 forengagement with the under side of the beam. Thus when pull rod 16 is raisedbeyond a predetermined point it movesbrake beam 51 counterclockwise about its pivot 50 in. opposition to the pressure of spring 64 and reduces the pressure on brake shoe 6 0, permitting the spool to turn morejfreely and reducingthe tension on wire 30. This motion is very slight. When there is no tension on the wire, nut 69 on. pull rod,16 is adjusted was to be out of contact with brake beam 51 and the brake pressure will depend solely on' the adjusted tension of spring 64. I

Referring to Figs,- 1, 2 andt3, the dual-tension spring unit to which the rear end of ar-in 21 is-connected=is--constructed asfollow s. An upper, relatively stifi, helical coilspring 70 is connected to a lower, relatively light helical coil spring 71 by a fitting 72 having a bore 74. This fitting is threaded at opposite ends, preferably with square threads, on which the ends of the two springs may be screwed. A similar single ended fitting 75, also having a bore, is screwed into the lower end of spring 71. Inside of spring 70 is a tube 76 and an end plug 78 which rests on top of the tube and engages the underside of the end loop 79 of the spring. Passing upwardly through the bores of fittings 75 and 72 and into the tube 76 is a draw-rod 80' having a stop-member or head 81 adapted to engage the upper face of fitting 72. The lower end of the rod 80 passes through a threaded fitting 82 (Fig. 3) which is held by a lock nut 84 in an inverted U-shaped tension adjusting bar 85 which extends across the back of with a cross shaft 96through bevel gears 98 so that the two screws can be rotated simultaneously by a crank 99. To permit rapid adjustment of the bar 85 to a predetermined position the bar may carry a pointer 100 which reads against a scale 101 attached to a stationary part of the frame, such as one of the pipes 10. Thus the tension on all wires may be changed simultaneously by turning crank 99.

One of the important aspects of the invention is the dual tension spring unit of Fig. 2, the construction of which has been generally described above and which will now be explained in more detail. It is this unit, in conjunction with the tension adjusting bar 85 or other means for varying the position of the anchored end of draw-rod 80, which provides the desirable wide range of possible tension adjustments. Heretofore when a great change in tension has been necessitated, for example by a shift from very fine to very heavy wire, it has been usual to substitute heavier for lighter springs, since, for the proper control of tension, a certain amount of deflection of the tension arms 21 is required which cannot be obtained with a light pull on a short stiff spring which would give such deflection only under a load in excess of that desired. Another but impractical way of providing a great change'in tension would be to use long springs which would have to be stretched through a great distance. By using the relatively short dual spring arrangement the advantages of long springs may be had without their disadvantages.

To illustrate the principle involved, let it be assumed that the light lower spring 71 is of such size and length as to have a spring rate of one inch of extension per pound of pull. provide a total tension range from zero to four pounds. A four pound pull elongates it to the point Where the head 81 on draw-rod 83 engages the fitting 72. so that any further pull on the unit through arm 21 is taken up by the upper heavier spring 70. The latter spring, for example, will have a spring rate of one inch of extension for two pounds of pull and it is placed under an initial tension, by means of tube 76 and plug 78 which are in seited in it for this purpose. This pretensioning is accomplished as follows. With the aid of suitable tension measuring devices a length of spring is determined which gives the desired spring rate, an allowance of the proper I .under a tension of four pounds when'the spring is coupled to fitting 72 is inserted in the spring and the fitting This spring is utilized, for example, to

screwed into the spring end. The plugs 78 serve a dual purpose. Being solid they provide durable stops-forengagement with the looped spring ends, which occurs with a blow when a wire breaks. Secondly, they can be made in a variety of lengths thus enabling tubes of uniform length to be used, the pretensioning adjustment being made by using the proper length of plug.

It is thus possible to make up a set of dual spring tension units all of which have the same operating characteristics. It thenbecomespossible to change'uniformly the tension of all the wires on the machine by movement of the adjusting bar 85 which stretches or relaxes all of the spring units to the same extent. By means of a calibrated scale such as 101 the tension of all units on of Figs. 4, 5 and 6. All brake pressures, on a machine assumed to have a plurality of tensioners, are initially set by compression of the springs 64 to be uniform, for example five pounds as measured at the brake shoe pivots 59 with a suitable gauge. The spring nuts 69 are adjusted to permit all of the pulley arms 21 to float, under any given wire tension, in approximately the same plane, for example horizontally, or in any other desired position intermediate their extreme positions, and to act on the brake beams 51 if their front ends move below that plane. As the machine is run the brakes are never full on or full ofi but maintain just enough friction on the brake drums to maintain the desired tension on the wires. Increased wire tension pulls arms 21 down and reduces this friction and vice versa.

Inevitably there is wear on the brake linings tending to reduce the wire tension and such wear will cause the front ends of'arms 21 to rise. If this condition were to be repeatedly corrected by moving spring nut 69, the end result would be a lengthening of spring 64 so that the maximum brake pressures determined by springs 64 would cease to be uniform. To avoid this, the above described separate wear adjustment isprovided in the screw acting on arm 52 which sets the brake shoe closer to the drum without changing the compression of spring 64. Hence, once adjusted, springs 64 and nuts 69 need not be touched again. It is easily determined when wear adjustment is required merely by watching the position of arms 21 as the machine is in operation. When one of them begins to rise out of the normal median plane of operation its corresponding screw 55 is merely turned down sufliciently to bring it back.

Summing up the operation of the tensioning device s above described, when consumption of wire 30 begins, as by winding it on a coil, the supply spool is held stationary by the brake until arm 21 rotates on its pivot to deflect the dual spring unit by a predeterminedamount, which depends on the position of the tension adjusting bar 85. This pulls arm 21 down to its operating position. The tension is maintained by the action of pull rod 16 on the brake beam 51 in reducing brake pressure as arm 21 moves below its operating position. This releases more wire from the spool and arm 21 returns, again increasing brake pressure and maintaining tension substantially uniform.

The term Wire as used in the claims is to be deemed inclusive of other filamentary materials comprising a single strand or multiple strands and other spoolable materials such as ribbon or tape with which tension devices are useful, the invention claimed being wholly indepeudent of the material being handled.

It is to be understood that the novel features of the mechanism as above described are not restricted in their use to the particular combination illustrated but may be used in combination with other parts-or elementsperforming like functions. As herein described they operate together, however, to produce a particularly advantageous single result, namely a smooth control of the tension of a plurality of wires or the like permitting a number of coils or spools to be uniformly wound. Many details of the construction described to illustrate the invention may, of course, be varied without departure from the invention as defined in the appended claims.

What is claimed is:

1. In a machine for simultaneously winding a plurality of coils, in combination, means for holding a plurality of spools of wire to be wound into coils, separate braking means acting to tension the wire drawn from each of said spools, pivoted arms having guide means over which each of the wires passes coupled with said braking means, a movable tension adjusting bar, tensioning springs attached at one end to each of said arms and at their other ends to said bar, and means for adjusting the position of said bar to simultaneously adjust the tension applied by said springs to said arms.

2. In a machine for simultaneously winding a plurality of coils, in combination, a plurality of spindles adapted to hold spools of wire to be wound into coils, separate braking means associated with each of said spindles and acting to tension the wire drawn from said spools, a

plurality of pivoted arms having guide means over which the wires individually pass, means coupling said arms with said braking means, a movable tension adjusting bar, means for adjusting the position of said bar, and tension springs anchored to said bar and connected to each of said arms, whereby the tension on all arms can be uniformly and simultaneously varied by moving said bar.

3. In a machine for simultaneously winding a plurality of coils, in combination, means for holding a plurality of spools of wire to be wound into coils, separate braking means acting to tension the wire drawn from each of said spools, a plurality of pivoted arms having guide means over which each of the wires passes coupled with said braking means, a movable tension adjusting bar, tensioning springs attached at one end to each of said arms and at their other ends to said bar, parallel rotatable screws having threaded connections with said bar, and means for simultaneously rotating said screws to position said bar and simultaneously adjust the tension of said springs.

4. In brake mechanism of the type comprising a brake drum, a brake shoe in frictional engagement therewith and subject to wear, a pivoted brake beam, and a spring acting on said beam to apply braking pressure to said shoe; the improvement which comprises the provision of an arm separate from said beam, said shoe being carried by said arm, means for pivotally supporting said arm for movement relative to said beam, and adjustable means for transmitting movement of said beam to said arm 5. The mechanism of claim 4 wherein said arm and said beam are mounted on a common pivot intermediate their ends, a compression spring is interposed between said arm and said beam on one side of said pivot, to

separate their adjacent ends, said shoe being supported by said arm on the other side of said pivot, and said adjustable means is also disposed on said other side of said pivot and adapted to act in opposition to the force of said compression spring to change the relative positions of said arm and beam.

6. The mechanism of claim 5 wherein said adjustable means is a screw.

7. A dual spring tension unit comprising a light spring and a heavier spring each of helical coil form arranged in end to end relationship, a coupling having a bore and connected with the adjacent ends of the two springs, a fitting having a bore attached to the other end of the light spring, a draw rod passing through the bores in said fitting and said coupling, means for fixing the posi tion of said fitting on said rod, a stop member on said rod adapted to limit the extension of the light spring by engagement with said coupling and thereby to transrnit the pull on the rod to the heavier spring, and means within the heavier spring pretensioning the heavier spring to the tension of the light spring at its maximum extension as determined by said stop member; said last mentioned means comprising a rigid tube adapted at one end to engage said coupling,-and a plug engaging the other end of said tube and the end of said heavier spring, the bore of said tube freely receiving said stop member, and the combined lengths of said tube and said plug being such as to maintain said heavier spring in a slightly extended position and under the tension exerted by the light spring at its maximum extension.

References Cited in the file of this patent UNITED STATES PATENTS 343,946 Chamberlayne June 15, 1886 511,251 Pickles Dec. 19, 1893 575,451 Yost Jan. 19, 1897 991,539 Pletsch May 11, 1911 1,589,435 Scott Jan. 22, 1926 2,126,296 Weihe Aug. 9, 1928 2,331,662 Delano Oct. 12, 1943 2,412,509 Johnstone Dec. 10, 1946 2,570,617 Wentz Oct. 9, 1951 2,607,543 Sutton Aug. 19, 1952 2,626,566 Pasquinelli Ian. 27, 1953 2,643,109 Wood June 23, 1953 FOREIGN PATENTS 404,181 France Oct. 13, 1909 OTHER REFERENCES Mechanical Springs published by The Wm. D. Gibson 00., Chicago, Ill. First Edition-copyright 1944, page 45. 

